I carried out adsorption experiment of 1ppm phenol from distilled water using commercial chitosan for 48 hr. Single beam UV spetrophotometer was used at 270nm . The absorbance value obtained after adsorption was higher than the absorbance value before adsorption (Blank sample) of the phenol solution leading to higher concentration after adsorption than before before adsorption.
Any accompanying phenomena falsify the result. However, to be able to answer reliably, more details are necessary. The process is batch I guess. So, can the volume of the mixture change during the process (decrease), eg due to the adsorption of the water? Do other analytical methods confirm this result? etc. Regards,
tps://www.tums.ac.ir/1395/03/09/BPA%20chitosan.pdf-hdehghani-2016-05-29-09-2